Improvement in thermostats for fire-alarms



UNITED STATES PATENTYOFFIGE.

GEORGE S. SHUTE, OF BOSTON, MASSACHUSETTS.

I'MPAROVEMENT IN T-I-iERMOST-ATS FOR FIRE-ALARMS.

Specification forming part of Letters Patent No. 207,139, dated August20, 187 application lileu' July 30, 1877.

To all whom it may concern:

Be it known that I, GEORGE S. SHUTE, of Boston, in the county ofSufl'olk and State of Massachusetts, have invented an Improvement inThermostatic Fire-Alarms, of which the following is a specification Thisinvention relates to a fire-alarm operated by heat and the inventionconsists in the combination, within a case provided with two apartments,one of which is more exposed to the influence of the atmosphere than theother, of two parallel bars or springs, each composed of two metals ofvarying degrees of expansibility, whereby, when the temperature of theroom in which the case is situated is raised suddenly above a certaindegree, as in case of fire, the bar or spring in the most exposedapartment will be deflected more than the other, and cause a finger orcircuit-closer supported and carried by one of the springs or bars tocome in contact with the other spring or bar, thereby closing anelectric circuit and setting in operation an alarm, either in the samebuilding or at a distance.

If both springs or bars are acted upon gradually, they will movetogether, and the circuit will not be closed until at or abovea certaintemperature, at which the springs'may be adjusted to close as their endsmove in the arc of a circle.

Figure l is a plan view of the case with the lid open; Fig. 2, a sideview of the case at the side of the most exposed apartment Fig. 3, alongitudinal section on the line a: m, Fig. 1; Figs. 4 and 5, end viewsof the case; and Fl 0 a 6, a side view of one of the springs or barsdisconnected or broken off, and laid on the inner side of the cover ofthe opened case of Fig. l.

The case a, made of metal or other suitable material, is provided with acover, b,and with a partition, 0, by which to divide the case into twoapartments, (1 c;

"The apartment d is supplied with air, chiefly through thepreferably-grated opening f and the'small opening y, made for thereception of the circuit-closing. finger h, attached to the spring a,which is supported in a block of wood or rubber, j, in the most exposedapartment 0, which has its side opened or exposed for the passage of airand heat, as at It, and its ends opened, as at l and m. The spring a inapartent d is connected with a block, 10, of wood or'rubber. Thisspringer bar a will be so held that by means of a screw, 1', arranged topress against one side thereof, the outer end, 2, of thespringorbarmaybecausedto assume aposition nearer to or farther from the downwardlybentend 3 of the finger h, as seen in dotted lines, Fig. 4.

In practice, the end 3 of the finger will rest at about one-eightlipf aninch from the end of the spring a but this distance may be more or less,as it is desired to close the circuit slower or faster, owing to asudden increase of tem-.

perature, as by fire.

Each spring has attached to its side a strip of a difl'erent metal, asat 4, so that the two metals composing each spring have differentdegrees of cxpansibilit'y under the action of heat.

If the room in which the case is located is quickly heated to adangerous degree, the atmosphere,eutering the most exposed apartment 0quickly and the least exposed apartment d slowly, causes the spring 6 tobe deflected faster and to a greater extent than the spring a, andconsequently the end 3 of the finger h, carried bythe spring or bar 1',will be brought against the end of spring a, and will complete theelectric circuit, the wires 5 6, connected with the springs or bars,being. properly joined on circuit, so as to sound an y usual alarm nearor at any desired distance or location.

This invention forms a very simple and cheap alarm, which may be placedin any building or room, and be connected with an alarm or signal to besounded, and which mayalso designate the room or the house, &c., ifcouncctcd on circuit with headquarters of firebrigade.

In practice, the springs n "i are tested before being placed in thecase, so as to select for each case two springs of like degrees ofexpansibility.

1 claim- A box or case having two apartments, one:

2 I sense springs or bars of difi'erent degrees of expan- In testimonywhereef 3 ave signed my name sibility, one inclosed in each of, theapartto this specification in the presence of two subinents, incombination with a circuit-closing scribing witnesses. finger, connecteddirectly with, and supported v and, carried. by, one of the springs orbars, GEORGE S. SHUTE. whereby,- when the more exposed bar is moved byheat monerapidly than the other, the finger Witnesses:

will connect the two bars to close an electric CHARLES Gums, circuit togive an alarm, substantially as set HENRY T. FITIS. forth.

